symfony2 很多设计模式思想，下面的资料会有点帮助：http://www.open-open.com/lib/view/open1414996676559.html
阅读目录
这是一些用PHP实现著名设计模式的示例代码。每个模式都有例子（其中大部分来自Zend框架，Symfony2或Doctrine2）。
Patterns
The patterns can be structured in roughly three different categories. Please click on the 
for a full explanation of the pattern on Wikipedia.
Creational
-
AbstractFactory
-
Builder
-
FactoryMethod
-
Multiton (is considered an anti-pattern!
) -
Pool
-
Prototype
- SimpleFactory
-
Singleton (is considered an anti-pattern! )
- StaticFactory
Structural
-
Adapter
-
Bridge
-
Composite
-
DataMapper
-
Decorator
-
DependencyInjection
-
Facade
-
FluentInterface
-
Proxy
-
Registry
Behavioral
-
ChainOfResponsibilities
-
Command
-
Iterator
-
Mediator
-
Memento
-
NullObject
-
Observer
-
Specification
-
State
-
Strategy
-
TemplateMethod
-
Visitor